package com.mycat.redis.stuff;

import com.dyuproject.protostuff.LinkedBuffer;
import com.dyuproject.protostuff.ProtostuffIOUtil;
import com.dyuproject.protostuff.Schema;
import com.dyuproject.protostuff.runtime.RuntimeSchema;
import org.objenesis.Objenesis;
import org.objenesis.ObjenesisStd;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * Protosuff序列化和反序列化工具类
 *
 * @author roger.
 * @email 190642964@qq.com
 * @create 2016-12-21
 */
public class ProtosuffUtil {

    /**
     * 缓存Schema的对象类型
     */
    private static Map<Class<?>, Schema<?>> cachedSchema = new ConcurrentHashMap<>();

    private static Objenesis objenesis = new ObjenesisStd(true);

    /**
     * 获取Protostuff的schema
     *
     * @param cls Schema的对象
     * @param <T> 对象类型
     * @return Schema<T>
     */
    private static <T> Schema<T> getSchema(Class<T> cls) {
        Schema<T> schema = (Schema<T>) cachedSchema.get(cls);
        if (schema == null) {
            schema = RuntimeSchema.createFrom(cls);
            if (schema != null) {
                cachedSchema.put(cls, schema);
            }
        }
        return schema;
    }

    /**
     * 序列化对象
     *
     * @param obj 需要序列化的对象
     * @param <T> 对象类型
     * @return byte[]
     */
    public static <T> byte[] serialize(T obj) {
        Class<T> cls = (Class<T>) obj.getClass();
        LinkedBuffer buffer = LinkedBuffer.allocate(LinkedBuffer.DEFAULT_BUFFER_SIZE);
        try {
            Schema<T> schema = getSchema(cls);
            return ProtostuffIOUtil.toByteArray(obj, schema, buffer);
        } catch (Exception e) {
            throw new IllegalStateException(e.getMessage(), e);
        } finally {
            buffer.clear();
        }
    }

    /**
     * 反序列华对象
     *
     * @param data 反序列化的byte[]
     * @param cls  反序列化后的对象Class
     * @param <T>  反序列化后的对象类型
     * @return 序列化后的对象
     */
    public static <T> T deserialize(byte[] data, Class<T> cls) {
        try {
            T message = objenesis.newInstance(cls);
            Schema<T> schema = getSchema(cls);
            ProtostuffIOUtil.mergeFrom(data, message, schema);
            return message;
        } catch (Exception e) {
            throw new IllegalStateException(e.getMessage(), e);
        }
    }
}
